. >> the anchor of pbs has sat in the madder rarts before. but in today's hyperpartisan world where everybody has an opinion facebook mr. lehrer is bound to wake up wake up tomorrow morning finding himself criticized by the left or right or both, our own senior political analyst brit. center of the attention and yet in a sense you don't want to be. you want the candidates to be the superior have to be firm enough and sharp in your questioning enough debate. you have to be careful to not ever cross the line where it looks like you are favoring one candidate over another. i think it's exceedingly challenging. >> challenging indeed. hard to find examples of anybody who has been offered the moderator job, shep and turned it down. >> shepard: you name a topic, can i tell you a complaint. in this we have heard complaints about a lack of diversity among the moderators. >> it's interesting. when you look at the three presidential debate moderators this year. candy crowley of cnn is only the second woman to moderate a debate. the first, in fact, for 2